Stem cell bait-and-switch
“I’ll never forget the woman whose knee was injected with stem cells to repair it, and came back two months later saying her skin on her face was smoother and more elastic. We hadn’t touched her face,” he says.
What makes the quote interesting is that it’s being advanced as evidence for, not against, the benefits of stem cells.
Injected stem-cells at least have the potential to work, though the story doesn’t mention any actual controlled trials or anything. What’s less plausible is the idea that rubbing messenger proteins (cytokines) from stem cells on your skin will have any effect. Despite the best efforts of small children, rubbing stuff on your skin doesn’t usually have the same effects as eating it or injecting it. Skin is there for a reason, and it’s quite good at keeping stuff out of your body, especially huge, fragile molecules like cytokines.
If new skin-care technologies really provided a benefit over ordinary moisturisers, it wouldn’t be hard to collect convincing evidence, as has been done for retinoid creams to treat acne, and chemical skin peels for various skin problems. Unfortunately, the new NZ law on unsupported health claims is just for foods and doesn’t apply to things you rub on your skin.
Thomas Lumley (@tslumley) is Professor of Biostatistics at the University of Auckland. His research interests include semiparametric models, survey sampling, statistical computing, foundations of statistics, and whatever methodological problems his medical collaborators come up with. He also blogs at Biased and Inefficient See all posts by Thomas Lumley »